翻閱程式發現以前在處理合併儲存格時，為該功能撰寫了最大公因數與最小公倍數的處理，這邊稍微整理記錄一下。
最大公因數的取法為使用遞迴去實作輾轉相除法，最小公倍數則是利用最大公因數與下面公式來計算：
程式碼
C# private int GCD(int num1, int num2) { int min = 0; int max = 0; int maxModMin = 0; min = Math.Min(num1, num2); max = Math.Max(num1, num2); maxModMin = max % min; return maxModMin > 0 ? GCD(min, maxModMin) : min; }
private int LCM(int num1, int num2) { return num1 * num2 / GCD(num1, num2); }
VB.NET
Private Function GCD(ByVal num1 As Integer, ByVal num2 As Integer) As Integer Dim min, max, maxModMin As Integer min = Math.Min(num1, num2) max = Math.Max(num1, num2) maxModMin = max Mod min Return If(maxModMin > 0, gcd(min, maxModMin), min) End Function
Private Function LCM(ByVal num1 As Integer, ByVal num2 As Integer) As Integer Return num1 * num2 / GCD(num1, num2) End Function
完整範例
C#
using System; using System.Collections.Generic; using System.Linq; using System.Text;
namespace ConsoleApplication1 { class Program { private static int GCD(int num1, int num2) { int min = 0; int max = 0; int maxModMin = 0; min = Math.Min(num1, num2); max = Math.Max(num1, num2); maxModMin = max % min; return maxModMin > 0 ? GCD(min, maxModMin) : min; }
private static int LCM(int num1, int num2) { return num1 * num2 / GCD(num1, num2); }
static void Main(string[] args) { const int EXAMPLE_COUNT = 5; const int MIN_RANDOM_VALUE = 2; const int MAX_RANDOM_VALUE = 50;
int num1, num2; Random ran = new Random();
Console.WriteLine(“GCD…”); for (int i = 0; i 0, gcd(min, maxModMin), min) End Function
Private Function LCM(ByVal num1 As Integer, ByVal num2 As Integer) As Integer Return num1 * num2 / GCD(num1, num2) End Function
Sub Main() Const EXAMPLE_COUNT As Integer = 5 Const MIN_RANDOM_VALUE As Integer = 2 Const MAX_RANDOM_VALUE As Integer = 50
Dim num1 As Integer, num2 As Integer Dim ran As New Random()
Console.WriteLine(“GCD…”) For i As Integer = 0 To EXAMPLE_COUNT - 1 num1 = ran.Next(MIN_RANDOM_VALUE, MAX_RANDOM_VALUE) num2 = ran.Next(MIN_RANDOM_VALUE, MAX_RANDOM_VALUE) Console.WriteLine(“GCD({0},{1}) = {2}”, num1, num2, GCD(num1, num2).ToString()) Next
Console.WriteLine() Console.WriteLine(“LCM…”) For i As Integer = 0 To EXAMPLE_COUNT - 1 num1 = ran.Next(MIN_RANDOM_VALUE, MAX_RANDOM_VALUE) num2 = ran.Next(MIN_RANDOM_VALUE, MAX_RANDOM_VALUE) Console.WriteLine(“LCM({0},{1}) = {2}”, num1, num2, LCM(num1, num2).ToString()) Next End Sub
End Module
運行結果如下：